The present invention relates to management of a rechargeable battery, and in particular, it relates to a battery management device and portal computer.
As the performance of the portable computer becomes better, there are more home users using it as a necessary electronic appliance.
The portable computer is equipped with a rechargeable battery, so that the portable computer can be used for a period without an external power supply.
However, for a commercial user, in most situations, most home users provide the portable computer with power by an external power supply at a fixed location.
For a conventional portable computer, upon power being supplied from the external power supply, the battery is taken out to preserve power. However, in this way, the portion covered by the battery, originally in the portable computer, is exposed; impurity can easily enter the inside of the portable computer through the exposed portion and cause damage to the portable computer, for example, it can cause an electrical shortage to occur.
If the battery is not taken out, a battery management method of the conventional portable computer often charges the battery in idle state, in which the state of charge of the battery is maintained at a high level (e.g., 99%), thereby such battery management method has the following defect.
The chargeable capacity of the rechargeable battery is closely related to the remaining amount of electrical charge of the battery in the idle state. Through the related experiments, it is found that the chargeable capacity of the battery is reduced by about eight percent when the fully-charged battery is stored for one year. The chargeable capacity of the battery is reduced only about four percent when the battery is 80% charged and stored for one year. If the battery is only charged to about 50%, after being stored for one year, the chargeable capacity of the battery is reduced by about one percent.
Therefore, the conventional battery management methods maintain the amount of electrical charge of the battery at a high level, which causes the chargeable capacity of the battery to attenuate.